POLARITON LUMINESCENCE IN MONOCLINIC ZNP2 CRYSTAL

Exciton polariton luminescence and its temperature dependence have been investigated in monoclinic ZnP2 crystals. The energies of transverse and longitudinal excitons (ET and EL) are determined by a fit of the reflection spectrum to a simple polariton model. In the vicinity of the 1s exciton, two emission bands are observed at energies ET and EL. They are attributed to the luminescence from lower and upper branch polaritons, respectively. In particular, the lower polariton luminescence band exhibits a well-defined doublet structure at 2 K. Both components are separated from each other by about 1 meV with comparable intensities and the same polarization dependence. With increasing temperature, the higher-energy component decreases rapidly as compared to the lower-energy component. The origin of these emission components is discussed. © 1990, THE PHYSICAL SOCIETY OF JAPAN. All rights reserved.